, here, and there, and we got you covered everywhere. with amy kellogg in a nervous london, and eric in times square, and sheryl outside fortress wall street, and rick leventhal in an anxious boston. we start with rick. >> a number of developments this afternoon, including a boston globe report that investigators found a circuit board believed to have triggered the bombs. they were made with pressure cookers, a style of explosive device found in afghanistan and pakistan. we learned that the saudi national who was tackled running from the scene, whose apartment was searched, has been cleared as a possible suspect, and they have re-opened part of boylston street as the shrink the crime scene and focus their efforts on the bomb site. we know investigators and atf and fbi are documenting every inch of payment, collecting every shred of possible evidence and they're asking for the puck's help to provide video or pictures taken near the finish line. it's call the most complex crime scene in the history of the city and the police are asking for breathing room. >> we want you to be vigilant.